<template>
  <div>
      <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
        <div class="iconfont header-abs-back">
            &#xe624;
        </div>
      </router-link>
      <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
          <router-link to="/">
           <div class="iconfont header-fixed-back">
               &#xe624;
            </div>
        </router-link>
          景点详情
      </div>
  </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop || document.body.scrollTop || window.pageYOffset
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  mounted () {
    window.addEventListener('scroll', this.handleScroll)
  },
  destroyed () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style  lang="stylus" scoped>
@import '~styles/varibles.styl'
.header-abs
    position :absolute
    left :.2rem
    top:.2rem
    width:.8rem
    height :.8rem
    border-radius:.4rem
    line-height :.8rem
    background :rgba(0,0,0,.8)
    text-align :center
    .header-abs-back
        color:#fff
        font-size:.4rem
.header-fixed
    position:fixed
    z-index :2
    top:0
    left:0
    right:0
    height :$headerHeight
    line-height :$headerHeight
    text-align :center
    color:#fff
    background :$bgColor
    font-size:.32rem
    .header-fixed-back
        position:absolute
        top:0
        left:0
        width :.64rem
        font-size:.4rem
        text-align :center
        color:#fff
</style>
